Re: [volt-nuts] How are femto-amps measured?
A simpler representation. http://www.edn.com/design/other/4381004/Femtoamp-fA-measurements Subject: Re: [volt-nuts] How are femto-amps measured? A simplest model is RC integration. http://electronicdesign.com/test-amp-measurement/whats-all-femtoampere-stuff-anyhow ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] How are femto-amps measured?
A simplest model is RC integration. http://electronicdesign.com/test-amp-measurement/whats-all-femtoampere-stuff-anyhow - Original Message - Subject: [volt-nuts] How are femto-amps measured? I saw the other day a Keithley 2636B SMU which has 0.1fA resolution @ 10uV in a normal Keithley DMM box size. Keithley also have some systems with external amps that go down even further, to tens of atto-Amp regions. Even the old HP resolves down to 1fA. It made me curious. Dear list: What's the basic principle of such measurements? ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] *WAY* too expensive for even Keysight to redesign
Yes, these folks do not market like the commercial side but there is a small industry supplying obsolete parts. They are not usually not focused to sell to the public. Sometimes, they just hunt around for NOS stored in some forgotten warehouse, then they test components to insure like new functionality. https://www.rocelec.com/obsolete-semiconductor-manufacturing/ http://www.xtremesemi.com/company_info.htm http://www.rfcafe.com/vendors/components/obsolete-components.htm As others have suggested, it likely will not be not cheap, so the cost to maintain old devices with obsolescent parts over the total cost of a redesign has to be a strong consideration. - Original Message - From: Daniel Mendes dmend...@gmail.com To: Discussion of precise voltage measurement volt-nuts@febo.com Sent: Wednesday, May 13, 2015 12:55:30 PM Subject: Re: [volt-nuts] *WAY* too expensive for even Keysight to redesign From the site you linked: Our life cycle management program assures you of a dependable, quality source of obsolete IC's forever. Now it was my turn of having a good laugh.. thanks for that, I didn´t knew that this service existed. Daniel ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] *WAY* too expensive for even Keysight to redesign
Sorry folks, sent too fast. Errors corrected. Yes, these folks do not market like the commercial side but there is a small industry supplying obsolete parts. They are not focused to sell to the public. Sometimes, they just hunt around for NOS stored in some forgotten warehouse, then they test components to insure like new functionality. https://www.rocelec.com/obsolete-semiconductor-manufacturing/ http://www.xtremesemi.com/company_info.htm http://www.rfcafe.com/vendors/components/obsolete-components.htm As others have suggested, it likely will not be cheap, so the cost to maintain old devices with obsolescent parts over the total cost of a redesign has to be a strong consideration. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Fwd: Old resistors
These look like resistance demonstrators for physics labs; slide potentiometers. Those devices were made very hardy back then, and while they can easily be replaced by a precision bournes pot or a used Tegam resistance box, you have it why not use it? Just make sure the contacts are clean and be wary with the conductors exposed, its a shock hazard. Given the printed rating its rated for 425 Watts, when it was new. At 05:03 PM 7/28/2013, Joseph Gray wrote: I know someone who has several of these old style resistors. Can anyone tell me anything about them? Are they of any use? https://dl.dropboxusercontent.com/u/19599147/Resistor%20-%20side.jpg https://dl.dropboxusercontent.com/u/19599147/Resistor%20-%20front.jpg Joe Gray W5JG __ The information contained in this transmission contains privileged and confidential information. It is intended only for the use of the person named above. If you are not the intended recipient, you are hereby notified that any review, dissemination, distribution or duplication of this communication is strictly prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. CAUTION: Intended recipients should NOT use email communication for emergent or urgent health care matters. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
